I got 4 back up plans setup a several weeks ago and it's been backing them up regularly ever since without issue. All good really, not needed to touch it in a while TBH.

I can report some further findings:
With 2.10.2.73 installed, I was unable to activate the license (even offline activation) . However when I updated to 3.0.0.100, I could activate my license fine.

3.0.0.100 seems to core dump regularly, in particular after hitting 'finish' when editing a backup plan. The cbbWebAccess process locked solid the once and need a kill -9 to renable the web interface.

I uninstalled 3.0.0.100, and then managed to cleanly install 2.10.2.73 without error. I suspect, now that I had manually installed the dependency libnsl various post install scripts executing cbb binaries now succeeded fine. So, possibly just need to add libnsl as a published dependency of the RPM package.

I'm still experimenting with various backup plans against local storage and BackBlaze B2, early days as my dataset is large, but appears to be mostly behaving thus far. I may have seen a handful of files it gets stuck on though...

Just working through similar issues, but I'm finding I have no directory:
/opt/local/CloudBerry\ Backup/etc/plans/

My install is in: /opt/local/CloudBerry Backup
And I have no etc/plans sub folders and no *.cbb files anywhere to be found.
My backup was configured to save plan config on the external storage (BackBlaze B2). So, I presume that's the only location of my .cbb files? In which case, how does one manage their permissions?

Further to this, is there a recommended approach to backing up multiple user home directories? Each user setup their own backup plan with their own permissions? Create a backup plan as root which has permission to read all user folders? Or add an admin-backup user to all user groups, and create plans under that user (assuming all user files are readable as their group)?